Sulfuric Acid → 9-Dehydroandrostenedione

Beteiligte Stoffe

Reaktionsschritte

9α-Hydroxyandrostenedione (9.07 g.) is added to aqueous sulfuric acid (22.5 ml. of 70%; 3 parts water and 7 parts sulfuric acid). The resulting slurry is stirred at 23°-25° until the reaction is complete as measured by TLC(ethyl acetate:hexane, 60:40). When complete the reaction mixture is cooled (10°) and added dropwise to ice-water (800 ml.) with rapid stirring. The resulting slurry is stirred overnight, filtered and the solids washed with water (500 ml.), sodium bicarbonate solution (10%, 500 ml.) and water (500 ml.). The solids are air-dried to give androsta-4,9(11)-diene-3,17-dione, 8.31 g. (97.4% chemical yield); m.p. 196°201°; [α]D +219° (chloroform); UV (methanol)λmax =240 nm (ε=16,500). GC (Example 1) shows an androsta-4,9(11)-diene-3,17-dione/androsta-4,8-diene-3,17-dione ratio of greater than 99 to 1.

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